Hydrophobic and nanoporous chitosan–silica composite aerogels for oil absorption

Abstract

Hydrophobic and nanoporous chitosan-silica composite aerogels with low density, high porosity, and superior oil absorbency were successfully prepared by a typical sol-gel method and a two-step hydrophobic treatment. The morphologies, porosity characteristics, mechanical properties, thermal stability, hydrophobicity, and oil absorbencies of the composite aerogels were systematically investigated. The nitrogen physisorption analysis showed that composite aerogels had large specific surface areas and uniform nanoporous structures. In addition, the composite aerogels could support 7000 times its own weight; this indicated the role of the supporting skeleton played by chitosan. The hydrophobicity and lipophilicity was demonstrated with a water contact angle of 137 and an oil contact angle of 0 . Importantly, the composite aerogel with 20 wt % chitosan had a relatively high oil absorbency of 30 g/g and could be reused up to 10 times. Therefore, the chitosan-silica composite aerogels in this study had a broad prospect to be used as efficient and recyclable oil absorbents.

Synthesis of organic aerogels with tailorable morphology and strength by controlled solvent swelling following Hansen solubility

“…However these aerogels contain inherently weak interlinks within their structure that lead to overall poor mechanical performance 17 . Making aerogels from inorganic-organic composites has been offered as a solution for these limitations 18 . An attractive approach to make aerogels is the use of nano-materials such as nanocellulose 19 and carbon nanotubes 20 , which are not solubilized but dispersed in appropriate media and have shown good mechanical stability, mainly due to presence of physical entanglements that provide ample contact points.…”

Properties of t‐zirconia prepared by a composite‐assisted nonhydrolytic sol‐gel

“…To this aim, we used the entrapment of a composite of chitosan (CS) within a ZrO 2 NNSG sol‐gel matrix. In the composite material (Ni@Si‐CS) the CS served as the sacrificial polymer template and as the carrier for dispersing the Ni dopant within the ZrO 2 gel . The silica (Si) was added to the composite to stabilize the CS framework during the zirconium NNSG process.…”

Biorefinery Approach for Aerogels

“…Crosslinker increases the number of pore walls inside the network, decreasing the pore size and increasing the specific surface area. Freeze dried samples obtained by Ma et al show a very high specific surface area for this type of drying thanks to the presence of silica aerogel inside chitosan network [282]. The ice crystals did not break the pores during the drying, conserving the nanopores, and allowing for a high specific surface area.…”